steezemcqueen
Moderator
i pulled the ones from my parts truck but 1sttoyotaparts.com has it for like $60
Questions About My 4x4 System
- Thread starter MDTrailrider
- Start date
i pulled the ones from my parts truck but 1sttoyotaparts.com has it for like $60
MDTrailrider
New member
Thanks Durk. I mostly use it for testing the voltage on my motorcycle battery and I used it to test the voltage on my 4Runner battery when it finally started to die. Believe it or not the 4Runner’s Panasonic factory original battery lasted 9 years! I guess that’s one of the benefits of parking vehicles in garages out of the sun and heat.
I would say I’m a beginner with multimeters. I’m at least a step or two above novice. The bigger mystery to me is testing electrical circuits on vehicles. I’ve never done that before. I didn’t know if I needed a tester that can tolerate greater amperage. I didn’t know if I could use a multimeter.
So there should always be vacuum going to the VSV’s and one VSV should always be open? I assumed that one of the VSV’s would momentary open to provide vacuum to one side of the actuator when the state of the manual lever is changed. I’m going to check the vacuum lines at the VSV’s as you suggest. I assume I just need to put my finger over the open end to see if a line is drawing air. I can get someone to move the transfer case lever while I check the operation of the VSV’s if it is a momentary event.
I suspect the problem is most likely a stuck A.D.D. I drove the 4Runner today in 4H to see if I could lubricate the front system and get it working. It didn’t work. I’m going to keep trying and see if it frees itself over the next several days. I’m hoping that driving the front differential with the propeller shaft will get oil flowing and pressurize it so it works its way into places where it had drained out and maybe capillary action will get it into the mated surfaces where it is stuck.
I’m also going to check the electrical circuits.
MDTrailrider
New member
Was that hard to do? Can that be done with the vehicle parked in the garage or do I need a lift?
TheDurk
Elite Member
I just looked at mine and noticed there is a check valve in the line from the manifold. Those can go bad too--on my e23 BMW it would kill the HVAC system when it clogged up. Worth checking, a $2 generic check valve from NAPA worked to fix the BMW. Just blow into both sides, one way flows, one way doesn't if it is good. Put it back the same way it was, obviously.
As to your question, the VSV's send vacuum continuously to the ADD. The vacuum goes through the splitter/manifold four-way thingy and there are lines out to each VSV and the reservoir. Those have full time vacuum. The other two lines that leave the VSV,s and go down to the actuator, also have full time vacuum, but only one at a time. So just pull one of those lines and put your finger on the nipple on the VSV (not the line) to see if it is drawing vacuum. Then replace and try the other one. Then switch the transfer lever and see if the vacuum moves to the other VSV's nipple. If there is no vacuum anywhere, look for leaks or blocks between the manifold and the VSV's. Check that each VSV is getting vacuum and work backwards.
Get this done before you worry about the electric part. My gut feel is you won't have to go there. The problem will more likely be in the actuator or the vacuum lines. But any old multi-meter works for this stuff if we have to go there.
As to your question, the VSV's send vacuum continuously to the ADD. The vacuum goes through the splitter/manifold four-way thingy and there are lines out to each VSV and the reservoir. Those have full time vacuum. The other two lines that leave the VSV,s and go down to the actuator, also have full time vacuum, but only one at a time. So just pull one of those lines and put your finger on the nipple on the VSV (not the line) to see if it is drawing vacuum. Then replace and try the other one. Then switch the transfer lever and see if the vacuum moves to the other VSV's nipple. If there is no vacuum anywhere, look for leaks or blocks between the manifold and the VSV's. Check that each VSV is getting vacuum and work backwards.
Get this done before you worry about the electric part. My gut feel is you won't have to go there. The problem will more likely be in the actuator or the vacuum lines. But any old multi-meter works for this stuff if we have to go there.
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steezemcqueen
Moderator
no lift needed. just take off the rear skid plate so you have a little more room to work and then its 4 bolts to take off the actuator
MDTrailrider
New member
Pure 98,
I’ve read your thread a few times. Your vacuum lines appear similar to mine.
If you’re sure your 4L works but not 4H then it must be related to the push button somehow. You’re A.D.D. has to be working if 4L works. The green 4x4 light will not come on if the A.D.D. does not engage the front drive shafts. It wouldn’t stick in 4H if it’s not sticking in 4L. A.D.D. performs the same exact function for 4H and 4L. I believe the lever activates the A.D.D. for 4L on your 4Runner and the magic button activates it for 4H. Can you drive it somewhere like on snow or ice, in mud or on wet rocks or roots to confirm that you have power at the front wheels in 4L? Get stuck somewhere in 2H and get out in 4L.
I think you should concentrate on the electrical components of your magic button. There are lots of electronic components, wiring harnesses and connections associated with that button that could be failing to make contact or are burned out. You probably need to start testing them. The online FSM tells you what circuits to test and where they’re located.
Pure 98
New member
I know for sure that 4L works I can fill it engage. The light dose come on and it has gotten me out of a lot of situations when I go offroading. I also think it is the push button and the electrical components. Yesterday I found a vacuum hose in the bottom of the car on the driver side that was plugged with a screw??? :shrug: Is that suppose to be like that?
MDTrailrider
New member
I don’t know but I doubt it. I also have no idea what the previous owner would have been solving by doing that. You should ask him or her if you can get in touch with the person.
It sounds to me like your command to enter 4H mode is not being executed somewhere between your finger on the 2-4 Selector Switch and the VSV’s or transfer case. It is also possible that there is something wrong at the transfer case that only affects 4H. I don’t think that’s likely though.
Have you tried looking at the Factory Service Manual at Toyota Tacoma/ 4Runner/ Tundra/ FJ Cruiser Factory Service Manual Page It’s about half way down the page with an image of a Desert Tan 4Runner. About half way down the FSM index is this page:
R.M. 2002::Transfer (Vf3am): Troubleshooting: Problem Symptoms Table (4Runner)
with a lot of links to the appropriate pages.
A little farther down are these two pages:
R.M. 2002::Transfer (Vf3am): One Touch 2-4 Selector System: Location (4Runner) and
R.M. 2002::Transfer (Vf3am): One Touch 2-4 Selector System: Inspection (4Runner)
that will walk you through checking your magic button.
I’ve learned a lot about my 4Runner by looking at this manual on and off during the past week.
MDTrailrider
New member
Halleluiah, I got my four wheel drive working!
I went out and started testing the VSV’s as TheDurk had recommended.
I pulled the blue line beyond the blue VSV with the engine running. I had no vacuum so I switched the transfer case to 4H. I still had no vacuum. Hmmmm that was not what I expected.
I reinstalled the blue line and pulled the source line coming from the intake manifold off of the little plastic vacuum manifold. I could immediately hear the vacuum hissing and felt it just to be sure.
I reinstalled the source line and pulled the unmarked line from beyond the brown VSV. It had vacuum. I returned the transfer case to 2H. Hmmmm I still had vacuum at the brown VSV. BTW, the vacuum is continuous.
Apparently my VSV’s were not changing state. I tried to determine if they are a one part set or individual valves. I couldn’t tell so I tried to pull the electrical wiring connector from the brown VSV. While I was doing that I decided instead to test the VSV vacuum in 4L first. I went back into the truck and noticed that my 4x4 light was on! I shifted back and forth between 2H, 4H and 4L. The light was going on and off as it should. I closed the hood and went for a test drive. I could immediately tell that I was in 4H. I drove around the neighborhood and turned it off when I was about to pull into the garage. Everything was working as it used to. I also slapped the bottom of the black vinyl cylinders on the VSV’s. I don’t know if one of the vacuum switching valves was sticking and that freed it or if they were not receiving the electrical signal directing them to switch and pulling on the brown connector restored continuity.
I learned a lot about my four wheel drive system and four wheel drive systems in general since Friday when I started trying to read things about it on and off to figure out what was wrong. The internet is great for this kind of problem solving. Nothing was actually broken. While trying to diagnose the problem I accidentally fixed it. If it ever stops working again I'll know right where to start looking. I’ll bet a Toyota stealer would have done about the same but charged me $1,400 or more for the repair.
I went out and started testing the VSV’s as TheDurk had recommended.
I pulled the blue line beyond the blue VSV with the engine running. I had no vacuum so I switched the transfer case to 4H. I still had no vacuum. Hmmmm that was not what I expected.
I reinstalled the blue line and pulled the source line coming from the intake manifold off of the little plastic vacuum manifold. I could immediately hear the vacuum hissing and felt it just to be sure.
I reinstalled the source line and pulled the unmarked line from beyond the brown VSV. It had vacuum. I returned the transfer case to 2H. Hmmmm I still had vacuum at the brown VSV. BTW, the vacuum is continuous.
Apparently my VSV’s were not changing state. I tried to determine if they are a one part set or individual valves. I couldn’t tell so I tried to pull the electrical wiring connector from the brown VSV. While I was doing that I decided instead to test the VSV vacuum in 4L first. I went back into the truck and noticed that my 4x4 light was on! I shifted back and forth between 2H, 4H and 4L. The light was going on and off as it should. I closed the hood and went for a test drive. I could immediately tell that I was in 4H. I drove around the neighborhood and turned it off when I was about to pull into the garage. Everything was working as it used to. I also slapped the bottom of the black vinyl cylinders on the VSV’s. I don’t know if one of the vacuum switching valves was sticking and that freed it or if they were not receiving the electrical signal directing them to switch and pulling on the brown connector restored continuity.
I learned a lot about my four wheel drive system and four wheel drive systems in general since Friday when I started trying to read things about it on and off to figure out what was wrong. The internet is great for this kind of problem solving. Nothing was actually broken. While trying to diagnose the problem I accidentally fixed it. If it ever stops working again I'll know right where to start looking. I’ll bet a Toyota stealer would have done about the same but charged me $1,400 or more for the repair.
MDTrailrider
New member
My girl friend and I went there this weekend. Are you still planning to come to town this week?
MDTrailrider
New member
Here are some final thoughts on this subject.
In answering one of my original questions, I suspect that 4WDemand means the vehicle is equipped with an Automatic Disconnecting Differential (A.D.D.).
I certainly wish that Toyota had been clear about that feature. To call it 4WDemand on the window sticker but A.D.D. in the Owner’s manual is unnecessarily confusing. I tried very hard to determine if I had A.D.D. when I read the owner’s manual twelve years ago because it was a feature I valued. It took reading a FSM that I did not have access to back then, figuring out how the appearance of the systems differed and then crawling under the vehicle to determine what the 4Runner did have. That’s ridiculous. Most vehicle owner’s either do not have the ability to read a FSM to figure it out or would never go through that much trouble to find out.
I had A.D.D. for twelve years but never took advantage of it because I was convinced that I did not have it. I could have used that feature many times. Even worse; I was supposed to be using it to keep it conditioned but I didn’t know better. Two years ago it started snowing while I was skiing. The snow had accumulated about an inch on the road by the time I went home. The rear tires suddenly broke traction going up a grade on a country road even though I had almost new tires. The truck fishtailed, went off the road sideways and hit a highway sign because I was driving in 2H. I would have shifted into 4H long before I lost control and wrecked if I knew I had A.D.D.
In answering one of my original questions, I suspect that 4WDemand means the vehicle is equipped with an Automatic Disconnecting Differential (A.D.D.).
I certainly wish that Toyota had been clear about that feature. To call it 4WDemand on the window sticker but A.D.D. in the Owner’s manual is unnecessarily confusing. I tried very hard to determine if I had A.D.D. when I read the owner’s manual twelve years ago because it was a feature I valued. It took reading a FSM that I did not have access to back then, figuring out how the appearance of the systems differed and then crawling under the vehicle to determine what the 4Runner did have. That’s ridiculous. Most vehicle owner’s either do not have the ability to read a FSM to figure it out or would never go through that much trouble to find out.
I had A.D.D. for twelve years but never took advantage of it because I was convinced that I did not have it. I could have used that feature many times. Even worse; I was supposed to be using it to keep it conditioned but I didn’t know better. Two years ago it started snowing while I was skiing. The snow had accumulated about an inch on the road by the time I went home. The rear tires suddenly broke traction going up a grade on a country road even though I had almost new tires. The truck fishtailed, went off the road sideways and hit a highway sign because I was driving in 2H. I would have shifted into 4H long before I lost control and wrecked if I knew I had A.D.D.
TheDurk
Elite Member
Yup--well, next week...I'll be there Sun-Tues.
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MDTrailrider
New member
Let me know if you want to get together at The Judges Bench and when. :cheers: I should be around. There's a chance we may go skiing but we should be able to work around that if we actually do go.
TheDurk
Elite Member
I may not have a chance. But if you could send a better contact to thedurk AT verizon DOT net, I'll certainly try.
That sucks but this thread doesn't. I found it researching what the oil capacity of the front diff on my 99 T4R is. Now I found that I most likely have A.D.D. also. Read the whole thread. Good info.
One thing I'm missing...
what's the advantage of the A.D.D.? I was under the impression it's just a way to minimize the amount of spinning parts when rolling in 2H, like manual locking hubs only less effective but more convenient.
Hi there, and greetings from Down Under
I've been searching the net for solutions as the 4WD on my 1993 SR5 Hilux is not engaging when i hit the auto-4WD switch on the 4H-4L lever (see pic).
After reading the post above on how MDTrailrider fixed his problem (I think the Surf has the same system as my Hilux SR5), i too started pulling vacuum tubes off, checking for vacuum and found while there was vacumm coming in, and coming out on the 'brown' side, there was no vacuum coming out on the 'blue' side (see pic), even after checking it with the 4WD button on/off and shifting between 4H and 4L.
One thing I noticed is one of those little black cylinders (which the mechanics etc tell me are just filters) is missing on the 'blue' side. But several mechanics etc have told me that will not cause the 4WD engage to fail.
So, i'm guessing that little blue electrical 'bit' (sorry - no idea what it is) has failed, hence no vacuum on that side?
Any thoughts? That whole mechanism in the second pic costs $800 to replace :wow2: (ie the VSV with the brown & blue bits etc), so i'm hoping an autoelectrician can just fix it?
mechanic fixed it (i think - have not actually tested that front wheels have drive yet) for about $150.
it was what he called 'worm drive gears' in the motor on the transfer case which engages drive to the front diff. These gears were siezed (but thankfully not stripped), so he took them out, greased them up and it appears to work again (i can hear that zzzzzzzz noise again now, when i hit the 4WD button on the move as things engage)
he also said that motor has a switch which cause power to flow to the solenoid on the VSV, and thus if that motor is not working, neither will the solenoid and hence i had no vacuum in that outward tube which runs down to the front diff and causes the auto-hubs to engage.
has been interesting to learn about all this
it was what he called 'worm drive gears' in the motor on the transfer case which engages drive to the front diff. These gears were siezed (but thankfully not stripped), so he took them out, greased them up and it appears to work again (i can hear that zzzzzzzz noise again now, when i hit the 4WD button on the move as things engage)
he also said that motor has a switch which cause power to flow to the solenoid on the VSV, and thus if that motor is not working, neither will the solenoid and hence i had no vacuum in that outward tube which runs down to the front diff and causes the auto-hubs to engage.
has been interesting to learn about all this
